With these high quality microfiber polishing pads, you not only avoid creating swirl marks in your paint by using a worn out pad, they also save you money by indicating when they are worn out. Never throw away a pad with use left again! A special super-soft microfiber covers a plush foam interior, and absolutely positively will not create swirl marks for the lifetime of the product - guaranteed! They work on this unique principal: Within every pad, are a series of metal spikes. When the pad is worn out, the foam breaks down, then the metal spines penetrate the cloth, and leave a visual indication on your vehicle, so you know when it's time to replace the pad! Compatible with any common buffer, or can also be used by hand.